I thought the multijet was a turbo charged diesel, but in the spec from Fiat in the little book they sent out it says this, "with supercharger and intercooler". Which is it?
turbo or supercharged?
turbo or supercharged?
General Multijet spec
- Thread starter Nuova500
- Start date
Currently reading:
General Multijet spec
OP
OP
ah bless em shame as a supercharger would eliminate any lag
shame as a supercharger would eliminate any lagah bless em
We've done 85,000 miles of testing with a 1.3 MJ engine with DPF's and have eliminated the lag on them. It was a real issue with these engines and an area that we concentrated on rather than ultimate power.
If you go back far enough any kind of forced air induction was referred to as Super ChargingI thought the multijet was a turbo charged diesel, but in the spec from Fiat in the little book they sent out it says this, "with supercharger and intercooler". Which is it?
Generally speaking you need quite a lot of space under the bonnet to house a supercharger, plus the fact that it needs to be driven by the bottom pulley which, if you look in the engine bay of a FWD car you'll find is about 3 inches from the inner wing. Then you have to mount the compressor itself on top of the engine which means you'll have to take the tin snips to the bonnet. Think you'll probably see why almost every forced induction system is on the turbocharged variety.
It will be an ECU remap I believe.
You can't effectively remove lag with a remap, lag is caused by the time it takes the engine to make enough exhaust gases to turn the turbo, therefore unless you change the turbo to a smaller one or quicker spooling ball bearing/twin scroll/variable geometry turbo's etc or do work to the breathing, like bespoke larger exhaust system to create less back pressure, the lag will always be there.
On a small engine like the 1.3, it just doesn't have the lungs to fill the turbo quickly enough, so lag will always be present, this is fundemental on any small turbo engine.
This is why on modern turbo cars the turbo's themselves are very small and built into the exhauist manifold before the CAT to make them as close to the engine as possible to eliminate lag as much as possible, though this has the down side of if you start to run more boost from the turbo you run the risk of overspeeding them shortening there life span, which also creates much more heat increasing inlet temperatures as well, so yes you will get more power to start with at determent of increased heat which on a hot summers day will negate any increases made. You can get round this by fitting an intercooler if it doesn’t have one, or fitting a bigger one, but then the inlet track is longer so this has effect on lag, its all a balancing act.
Car manufacturers spend millions developing engines now to be built to very tight tolerances, and to make them drive as best as possible with very flat torque curves. The engines also spend hundreds of hours on test beds going through long term durability testing to ensure that they will meet and exceed requirements, this can’t be replicated on the road by aftermarket manufacturers.
Don't get me wrong, I love tuning cars, but modern cars are built now to a cost and specification to meet pretty exacting standard and this makes it much tougher for aftermarket tuners get more out of them, yet retain the reliability.
they are also built to be reliable in conditions much worse than the UK, so there is still quite a lot of room to manouvre
PEZZ175
New member
- Joined
- Feb 4, 2008
- Messages
- 182
- Points
- 29
This is interesting. Does this mean that you think remapping turbo diesels is a bad idea? I haven't heard of one bad experience so far.
Last edited:
OP
OP
Im not getting mine done, thats for sure... if I didnt like it as is, then I wouldnt have bought it in the first place. Still too many issues with remapping for my liking, heard plenty of horror stories.
PEZZ175
New member
- Joined
- Feb 4, 2008
- Messages
- 182
- Points
- 29
What stories?
- Joined
- Apr 26, 2007
- Messages
- 13,617
- Points
- 2,161
Share them please... there are many on here would like a good, balanced technical discussion.
If you ever see the torque curves of a modern turbo car, no matter if its petrol or deisel the torque curve is very flat, this makes the car effortless to drive, giving a wide spread of torque, they achieve this by using the ECU and wastegate control, though this is hardly new science, even old cars like integrale's had ECU/wastegate control to give less boost in lower gears to preserve the drive train.
On the most modern of cars with fly-by-wire throttle this is taken further, by using the abs sensors the ECU can sense wheel spin and it actually adjusts the amount of throttle appllied as it works out exactly how much torque can be transferred to the wheels, so even if your foot is flat to the floor, you are not getting full throttle,and because there is no cable to attach your foot peddle to the throttle body you do not perceive any difference, you no longer have as much control over your car as you did with cable opperated throttle control.
What many re-mappers do is lift some of the safety elements of the boost control, so that you get full boost in lower gears making car faster, or let the boost rise higher at higher rpm rather than flatten out, giving a big surge in power/torque which feels good as a big sruge intorque is what is felt by the human body in the acceration of the car, so feels faster.
What this can lead to, not saying it always will, is the clutch and all drivetrain components getting excessive wear, though in general this will not be felt until the car has covered a fair few miles. The only thing sensed by you the owner is probably more tyre wear, and the traction control ABS functions being alerted more by the excess power trying to be transmitted to the road.
There are some good very clever people out there that understand all these elements that are controlled by the ECU and can work with them ensuring that there is still safety margins built in, and ulimately the car still drives superb, maybe even better than before, but in general all these people work on the cars as given to them, and don't just flash a universal map onto the car.
On the most modern of cars with fly-by-wire throttle this is taken further, by using the abs sensors the ECU can sense wheel spin and it actually adjusts the amount of throttle appllied as it works out exactly how much torque can be transferred to the wheels, so even if your foot is flat to the floor, you are not getting full throttle,and because there is no cable to attach your foot peddle to the throttle body you do not perceive any difference, you no longer have as much control over your car as you did with cable opperated throttle control.
What many re-mappers do is lift some of the safety elements of the boost control, so that you get full boost in lower gears making car faster, or let the boost rise higher at higher rpm rather than flatten out, giving a big surge in power/torque which feels good as a big sruge intorque is what is felt by the human body in the acceration of the car, so feels faster.
What this can lead to, not saying it always will, is the clutch and all drivetrain components getting excessive wear, though in general this will not be felt until the car has covered a fair few miles. The only thing sensed by you the owner is probably more tyre wear, and the traction control ABS functions being alerted more by the excess power trying to be transmitted to the road.
There are some good very clever people out there that understand all these elements that are controlled by the ECU and can work with them ensuring that there is still safety margins built in, and ulimately the car still drives superb, maybe even better than before, but in general all these people work on the cars as given to them, and don't just flash a universal map onto the car.
Last edited:
OP
OP
Im not getting into sharing tales of woe regarding remaps, but there are plenty of cars whove had remaps and had problems, also remaps that have actually reduced the BHP of a car.
J333 is talking a lot of sense here, listen to him
J333 is talking a lot of sense here, listen to him
PEZZ175
New member
- Joined
- Feb 4, 2008
- Messages
- 182
- Points
- 29
Thanks for the info
These are good views. I would like to point out that if it's a good remap company they will always work within the tolerences of the cars components and, in some cases, these guidelines are given to them directly from the manufacturer themselves. This combined with sensible treatment and not driving like a twerp will keep the car performing (certainly in the case of diesels) and driving far better than before.All this is too good to be true in terms gains vs how little you've actually spent but personally I still have issues with the ever cloudy line regarding total warranty rights and dealership approval. If anything would put me off a remap it would be this as the question has never been answered categorically.
PEZZ175
New member
- Joined
- Feb 4, 2008
- Messages
- 182
- Points
- 29
Im not getting into sharing tales of woe regarding remaps, but there are plenty of cars whove had remaps and had problems, also remaps that have actually reduced the BHP of a car.
J333 is talking a lot of sense here, listen to him
I will
Try searching on the internet (ultimate source for info don't ya know) for bad remap experiences. Surely there'd be something documented there
It's a different car, but I do know of someone who owns a Suzuki Ignis Sport who had his car remapped by a very large and well know remapping company and got a nice rolling road print out to show how much better than car now was.
By a strange turn of events he ended up getting an apprenticeship at another car tuning company about 6 months later, a stand alone company who have gained a good name for there mapping prowess, but not just on standard ECU's, but standalone units, so proper full mapping services.
He had some issues with the original ECU and sent it back to remapping company who said they would repair it, and in mean time he sourced a 2nd hand ECU to run his car. The repaired "mapped" ECU returned and he refitted thinking all was well.
One evening when the r/r operator was finished up what he was doing he said to bring the Ignis in and give it a proper run up see what it was doing. The "remapped" ECU produced a figure that was some 15bhp down on what remapping company produced, odd he thought, so stuck inthe spare ECU he had, the car made 1bhp more and the fuelling according to the totally impartial r/r operator was much much better, his comments were the remapped EUC just had the fuelling increase, needless to say he returned to remapping company and asked them to explain, they of course gave many excuses, from we must have erased map when we fixed it, to the air pressures were different to you name it they said it.
He started researching other instances and found that there are many cases out there of supposed remaps that do nothing, though they are still in minority to those who do a professional job and do give true gains.
What this demonstrated was that, one its very easy to give false readings on a r/r, and two its not that easy remapping cars, especially N/A where you can't just change the boost levels, there is only so much you can do with fuelling and ignition.
Oh and not everyone has access to a r/r to play with to ensure what they have been sold matches its description.
By a strange turn of events he ended up getting an apprenticeship at another car tuning company about 6 months later, a stand alone company who have gained a good name for there mapping prowess, but not just on standard ECU's, but standalone units, so proper full mapping services.
He had some issues with the original ECU and sent it back to remapping company who said they would repair it, and in mean time he sourced a 2nd hand ECU to run his car. The repaired "mapped" ECU returned and he refitted thinking all was well.
One evening when the r/r operator was finished up what he was doing he said to bring the Ignis in and give it a proper run up see what it was doing. The "remapped" ECU produced a figure that was some 15bhp down on what remapping company produced, odd he thought, so stuck inthe spare ECU he had, the car made 1bhp more and the fuelling according to the totally impartial r/r operator was much much better, his comments were the remapped EUC just had the fuelling increase, needless to say he returned to remapping company and asked them to explain, they of course gave many excuses, from we must have erased map when we fixed it, to the air pressures were different to you name it they said it.
He started researching other instances and found that there are many cases out there of supposed remaps that do nothing, though they are still in minority to those who do a professional job and do give true gains.
What this demonstrated was that, one its very easy to give false readings on a r/r, and two its not that easy remapping cars, especially N/A where you can't just change the boost levels, there is only so much you can do with fuelling and ignition.
Oh and not everyone has access to a r/r to play with to ensure what they have been sold matches its description.
Last edited:
Which is why you should go to a reputable company and get a before and after RR
I only wish nuovapanda would share is tales of woe
And Suzuki ECU's are as dodgy as hell, I speak from experience
